Various types of cellular communication systems are known to provide radio telephone service to a large number of mobile subscribers using a relatively small number of frequencies. Such service is provided by dividing a service area into a number of cells and reusing the frequencies in non-adjacent cells. This cellular principle has permitted a large growth in the amount of wireless telecommunications that may be carried over the allocated radio spectrum thus providing significant expansion in the number of wireless communication subscribers. Various different cellular protocols include analog, time division multiple access (TDMA), code division multiple access (CDMA), Global System for Mobile Communications (GSM).
Similarly, various types of wireline systems and protocols provide different wireline services to a large number of users who typically utilize personal computers and other types of computing devices to access these services. Different wireline protocols and services include mobile or voice over IP (internet protocol), Authentication, Authorization, and Accounting (AAA), Session Initiation Protocol (SIP), and H.323 protocol that provides packet-based multimedia communication systems.
In many wireless communication systems, Home Location Registers (HLRs) and Visitor Location Registers (VLRs) are used to handle mobility management. HLRs and VLRs potentially may reside anywhere in the network. An HLR contains profile information for each of its mobile subscribers and the address of the current VLRs for each mobile. Each Mobile Switching Center (MSC) has a VLR that tracks mobiles currently receiving service in the serving MSC's coverage area. Whenever a mobile enters an area served by a new VLR and registers there, the latter informs the mobile's HLR of the change in the mobile's location. In addition, the VLR downloads the service profile of the roaming mobile as well as other information necessary for call termination at the mobile. During call delivery, the location and profile information in the HLR is utilized to route incoming calls to the mobile.
Mobile data communication systems utilize network servers called home agents and foreign agents to provide analogous functions to HLRs and VLRs, respectively. Wireline communication systems utilize functions such as authentication, service provisioning, user profile management, user location management, and service invocation.
As communication systems evolve and provide increased services, mobile users require more services, including roaming between and access to each different system. Issues regarding mobility management between these systems need to be resolved.
Accordingly, there is a need for a method and apparatus to provide mobility management for users between multiple systems utilizing different protocols.